This invention relates to methods of obtaining NMR spectra from a region lying wholly within a sample, and has application, for example, in obtaining NMR spectra from within living bodies. An example of one technique for obtaining information of this kind is disclosed in U.K. Patent Application No. 8303501 (now published as No. 2,114,756). There is also disclosed in U.K. Patent Specification No. 2056088 a method of imaging a region lying within another region. However, this technique is not suitable for obtaining spectral data.